Use this chemistry calculator to reproduce a named relationship with explicit quantities and units for study, laboratory planning, or an independent numerical check.

Reactant pressure (atm)

Current reactant partial pressure; must be greater than zero.

Product pressure (atm)

Current product partial pressure; must be greater than zero.

Reactant coefficient

Reactant stoichiometric coefficient.

Product coefficient

Product stoichiometric coefficient.

Compute the reaction quotient in terms of partial pressures as Qp = P_B^b / P_A^a for aA ⇌ bB. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Qp

Reaction quotient based on partial pressures.

• Equilibrium expressions must match the balanced reaction and selected standard state. Concentrations or partial pressures may not equal activities at non-ideal conditions, and a calculated equilibrium constant does not describe how quickly equilibrium is reached.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check units and significant figures, compare the result with limiting cases, and use measured or source-specific constants where available. Laboratory, safety, and regulatory decisions require validated methods and appropriate uncertainty analysis.

• Kp From Partial Pressures Calculator

  Compute the pressure-based equilibrium constant Kp = P_B^b / P_A^a for a reversible reaction aA ⇌ bB.

• Kc From Concentrations Calculator

  Compute the concentration-based equilibrium constant Kc = [B]^b / [A]^a for a reversible reaction aA ⇌ bB.

• Equilibrium Shift Checker

  Compare the reaction quotient Q against the equilibrium constant K to determine the direction of shift.